Effect of exposure to 2,5-hexanediol in light or darkness on the retina of albino and pigmented rats. II. Electrophysiology

Abstract

Albino (Sprague-Dawley) and pigmented (Norwegian Brown) male rats were exposed to 2,5-hexanediol (H; 1%) in their drinking water for 5 or 8 weeks, respectively. Half of the rats of each strain were housed in light (average 30 cd/cm2 inside cage, 12 h/day); the other half was kept in constant darkness. Control groups were studied in parallel under identical conditions but without H. Electrophysiological recordings were made 2-5 days and 13 weeks after the end of the exposure to H. Alterations in the visual system, as measured by electroretinography and visual evoked response, were found in groups of albino rats exposed to H and/or light. The pupillary diameter was enlarged in the albino group exposed to both H and light. Among the pigmented rats, alterations were recorded only in the visual evoked response of the H exposed groups. The results demonstrate that simultaneous exposure to H and light can lead to alterations in visual function that are more severe than those induced by each agent alone, and may exceed a simple summation.

Function of the Auditory and Visual Systems, and of Peripheral Nerve, in Rats after Long‐Term Combined Exposure to n‐Hexane and Methylated Benzene Derivatives. I. Toluene

“…The small responses were probably mainly due to lightinduced retinal damage. Recently, retinal alterations have been found (Nylen et al 1993) after about half a year of exposure to ambient light intensities lower than those used in the present study.…”

“…The dysfunction within the visual pathway in the H group 2 days after exposure, indicated by reduced amplitudes of the N 1 P2 (P < 0.05), and by trends towards decrease in the P l N l amplitude and prolongation of the 3 latencies, had disappeared 3 months later. Functional, but also structural, regeneration of the visual pathway has also been reported in rats exposed to 2,5-hexanediol (Jones & Cavanagh 1982;Nylen et al 1993). A reduction of the NIP2 amplitude was seen also in the T group 2 days after exposure.…”

Progress in retinal toxicity research

“…Much later, significant advance of diagnostic tools, such as electroretinographic assessment of early retinopathy in rats (Maertins et al 1993 ), triggered a new era of research on retinotoxins, by combining morphological and physiological methods (Nyska et al 1992 ). Examples of toxicants examined are 2-hexanediol (Bäckström et al 1993 , 1998 ; Nylen et al 1993 ) and the antibacterial agent sitafloxacin (Shimoda et al 2001 ).…”